Raynaud’s Disease (ra-’noz) n: a constriction of the blood vessels brought on by cold or stress that causes a discoloration of the fingers and toes

For many people, a drop in the temperature means acute pain and a disruption in normal activities. That’s because up to 15% of the population suffers from Raynaud’s phenomenon, a medical condition that causes blood vessels to spasm, blocking blood flow to parts of the body and causing a dramatic change in the color of the skin. The discoloration of the skin often comes in what is known as a “three-phase sequence,” which means the skin turns from white to blue to red. First, the blood vessels spasm and reduce the flow of blood, turning the affected area white. After a period without oxygen, the area begins to turn blue. Finally, the spasm stops and the blood vessels reopen. Blood rushes to the area, turning it red.

The cycle can be quite painful to sufferers. “At first, you feel a tingling in the tips of the fingers, and then a sort of numbness,” says Samantha Kubik, a Raynaud’s sufferer from Johnson City, N.Y. “It feels like threading down the fingers to the knuckles.” Kubik says that when she realizes she is going to experience an episode, she immediately begins to get prepared to handle it: rubbing her fingers, moving her arms, reaching for gloves. “Your fingers stop doing what they’re supposed to do,” she says. “If you’re driving, it’s hard to grasp the wheel; the cold air is very painful. You feel like your fingers are beginning to freeze,” says Kubik. Though Raynaud’s affects only Kubik’s hands, the condition can also disrupt the blood flow to the feet, nose, ears, and even, though rarely, the tongue.

Most of the time a change in the weather triggers a spasm of the blood vessels that cause Raynaud’s. However, stress has also been noted as a factor. The Raynaud’s Association explains the reason: Our blood vessels normally constrict when we experience strong emotions. Since patients with Raynaud’s have overactive vessels, the release of adrenaline during stress can trigger a spasm, making the vessels too narrow and preventing blood from flowing correctly.

There are two types of Raynaud’s phenomenon: primary and secondary. Think of primary Raynaud’s as a stand-alone phenomenon that isn’t related to any other medical problem. Secondary Raynaud’s is caused by a larger health problem, such as lupus or rheumatoid arthritis. The Raynaud’s Association notes that primary Raynaud’s is “not usually debilitating in the typical sense, but sufferers can experience great discomfort and pain — requiring lifestyle adjustments to minimize exposure to cold and stress.” Those with secondary Raynaud’s on the other hand, “are more likely to suffer more serious problems, such as skin ulcers (which can cause serious long-term damage to the blood vessels), or even gangrene.”

Though doctors know what is happening — the blood vessels spasm and prohibit proper blood flow — they don’t know why it happens. They do know that women are more likely to develop Raynaud’s than men, and most often, it is diagnosed between the ages of 20-40. Though very little is known as to the cause of Raynaud’s, there are links that doctors acknowledge. For example, some occupations that require the use of vibrating, handheld machinery cause nerve damage that results in Raynaud’s. (Don’t get nervous; we’re talking jackhammer, not electric file.) Some people with migraines also suffer from Raynaud’s but why there is a link remains uncertain. Most of the links that doctors see are with patients who suffer from secondary Raynaud’s, leaving the root cause of the vessel spasm in Raynaud’s a mystery. To further complicate the data, many people who suffer with Raynaud’s wait years to consult a doctor. The reason for this is that while the condition is painful and may even reduce one’s ability to perform tasks, the fl are-ups eventually pass. So many people simply adapt to the inconvenience by doing all they can to keep warm.